Trace element modification of iron-rich phase in aluminum-silicon alloys to accommodate high iron content

ABSTRACT

Methods and heat-treated cast aluminum alloy components for a vehicle formed from an aluminum alloy having high levels of recycled aluminum scrap are provided. The alloy may have, by mass, silicon at ≥5% to ≤11%, magnesium at ≤0.5%, iron at ≥0.2% to ≤1.1%, copper at ≤0.5%, zinc at ≤0.5%, titanium at ≤0.2%, chromium at ≤0.02%, manganese at ≤0.05%, strontium at ≤200 ppm; an alloying element at ≥50 ppm to ≤500 ppm selected from the group consisting of: barium, lanthanum, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and combinations thereof, and a balance aluminum. The heat-treated cast aluminum alloy component is substantially free of faceted iron-containing intermetallics having a platelet shape and at least one region has a yield strength of ≥180 MPa and an elongation of ≥7%.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit and priority of Chinese Application No. 202210703322.7 filed Jun. 21, 2022. The entire disclosure of the above application is incorporated herein by reference.

INTRODUCTION

This section provides background information related to the present disclosure which is not necessarily prior art.

The present disclosure generally relates to cast aluminum alloy components having high tolerance for iron impurities and, more particularly, to vehicles including recyclable cast aluminum-silicon alloy components having relatively high iron content and methods for making such cast aluminum alloy components.

Lightweight metal components for vehicle (e.g., automotive) applications are often made of aluminum and/or magnesium alloys. Such lightweight metals can form load-bearing components that are strong and stiff, while having good strength and ductility (e.g., elongation). High strength and ductility are particularly important for vehicles, like automobiles.

Recycling of aluminum alloy components is desirable for energy savings, reduction in generation of carbon dioxide and other pollutants, and sustainability. However, recycled post-consumer aluminum scrap often contains relatively high levels of iron as an impurity. Traditionally, high levels of iron in aluminum alloys have been avoided, because iron can combine with silicon and aluminum to form iron-rich intermetallics, which tend to act as crack initiators in deformation, degrading fracture toughness, ductility, and fatigue durability of aluminum-silicon casting. For example, for production of knuckle and road wheels in vehicles, iron content in an A356 aluminum alloy is controlled to be less than 0.15 wt. %. However, to satisfy the limitation of iron being less than 0.15 wt. %, only a very limited fraction of recycled aluminum scraps can be used. Thus, it would be desirable to be able to increase an iron tolerance in cast aluminum alloy products so that additional recycled post-consumer aluminum can be added to enhance sustainability of such products, while mechanical performance is not diminished.

SUMMARY

This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

The present disclosure relates to heat-treated cast aluminum alloy components. For example, in one variation, the present disclosure provides a heat-treated cast aluminum alloy component for a vehicle formed from an aluminum alloy. The aluminum alloy may include silicon (Si) at greater than or equal to about 5% to less than or equal to about 11% by mass, magnesium (Mg) at less than or equal to about 0.5% by mass, iron (Fe) at greater than or equal to about 0.2% to less than or equal to about 1.1% by mass, copper (Cu) at less than or equal to about 0.5% by mass, zinc (Zn) at less than or equal to about 0.5% by mass, titanium (Ti) at less than or equal to about 0.2% by mass, chromium (Cr) at less than or equal to about 0.02% by mass, manganese (Mn) at less than or equal to about 0.05% by mass, strontium (Sr) at less than or equal to about 200 ppm, an alloying element at greater than or equal to about 50 ppm to less than or equal to about 500 ppm, wherein the alloying element is selected from the group consisting of: barium (Ba), lanthanum (La), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and combinations thereof, and a balance aluminum (Al). The heat-treated cast aluminum alloy component is substantially free of faceted iron-containing intermetallics having a platelet shape and at least one region has a yield strength of greater than or equal to about 180 MPa and an elongation of greater than or equal to about 7%.

In one aspect, the aluminum alloy includes greater than or equal to about 70% of aluminum recycling scrap.

In one aspect, the aluminum alloy includes iron (Fe) at greater than or equal to about 0.25% by mass.

In one aspect, the aluminum alloy includes iron (Fe) at greater than or equal to about 0.4% by mass.

In one aspect, the aluminum alloy includes silicon (Si) at greater than or equal to about 6.5% to less than or equal to about 8% by mass, magnesium (Mg) at greater than or equal to about 0.3% to less than or equal to about 0.4% by mass, iron (Fe) at greater than or equal to about 0.2% to less than or equal to about 0.6% by mass, copper (Cu) at less than or equal to about 0.1% by mass, zinc (Zn) at less than or equal to about 0.1% by mass, and the alloying element at greater than or equal to about 50 ppm to less than or equal to about 300 ppm.

In one aspect, the aluminum alloy includes: silicon (Si) at greater than or equal to about 6.5% to less than or equal to about 8% by mass, magnesium (Mg) at greater than or equal to about 0.3% to less than or equal to about 0.4% by mass, iron (Fe) at greater than or equal to about 0.4% to less than or equal to about 0.8% by mass, copper (Cu) at less than or equal to about 0.1% by mass, zinc (Zn) at less than or equal to about 0.1% by mass, and the alloying element at greater than or equal to about 50 ppm to less than or equal to about 300 ppm.

In one aspect, the heat-treated cast aluminum alloy component includes an iron-containing intermetallic that has a non-faceted rounded morphology.

In one aspect, the heat-treated cast aluminum alloy component includes an iron-containing intermetallic including iron (Fe), silicon (Si), and aluminum (Al) and after heat treatment, the iron-containing intermetallic is spheroidized and has an average equivalent diameter of greater than or equal to about 1 micrometer to less than or equal to about 5 micrometers.

In one aspect, the alloying element is selected from the group consisting of: barium (Ba), samarium (Sm), europium (Eu), erbium (Er), and combinations thereof.

In one aspect, the heat-treated cast aluminum alloy component is an automotive component.

In one aspect, the yield strength is greater than or equal to about 210 MPa.

In one aspect, the heat-treated cast aluminum alloy component is an automotive component selected from the group consisting of: an internal combustion engine component, a valve, a piston, a turbocharger component, a rim, a wheel, a subframe, a knuckle, a control arm, a ring and combinations thereof.

The present disclosure also relates to a method of making a recycled aluminum alloy component including melting an aluminum alloy precursor including greater than or equal to about 70% by mass aluminum recycling scrap to form a molten alloy. The aluminum alloy precursor has a composition including silicon (Si) at greater than or equal to about 5% to less than or equal to about 11% by mass, magnesium (Mg) at less than or equal to about 0.5% by mass, iron (Fe) at greater than or equal to about to less than or equal to about 1.1% by mass, copper (Cu) at less than or equal to about 0.5% by mass, zinc (Zn) at less than or equal to about 0.5% by mass, titanium (Ti) at less than or equal to about 0.2% by mass, chromium (Cr) at less than or equal to about 0.02% by mass, manganese (Mn) at less than or equal to about 0.05% by mass, strontium (Sr) at less than or equal to about 200 ppm, and a balance aluminum (Al). The method also includes introducing a master alloy into the molten alloy. The master alloy includes a matrix element selected from the group consisting of: aluminum (Al), magnesium (Mg), silicon (Si), and combinations thereof and an alloying element selected from the group consisting of: barium (Ba), lanthanum (La), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and combinations thereof. The method includes casting by solidifying the molten alloy at a maximum rate of cooling of less than or equal to about 20° C./second to form an as-cast recycled aluminum alloy component. The method also includes heat treating the as-cast recycled aluminum alloy component to be substantially free of faceted iron-containing intermetallics having a platelet shape and to have at least one region having a yield strength of greater than or equal to about 180 MPa and an elongation of greater than or equal to about 7%.

In one aspect, the alloying element is present in the master alloy at greater than or equal to about 5% to less than or equal to about 30% by mass.

In one aspect, the master alloy is added at greater than or equal to about 0.01% to less than or equal to about 2.5% by mass to the molten alloy.

In one aspect, the method further includes: (i) melt refining of the molten alloy and degassing prior to the introducing the master alloy, (ii) melt refining of the molten alloy and degassing after the introducing the master alloy and prior to the casting, or both (i) and (ii).

In one aspect, the heat treating includes tempering the as-cast recycled aluminum alloy component at a temperature of greater than or equal to about 500° C. to less than or equal to about 550° C. for greater than or equal to about 1 hour to less than or equal to about 10 hours.

In one aspect, the heat treating includes ageing the as-cast recycled aluminum alloy component at a temperature of greater than or equal to about 130° C. to less than or equal to about 190° C. for greater than or equal to about 1 hour to less than or equal to about 10 hours.

In one aspect, the method further includes quenching after the heat treating with water at a temperature in the range of greater than or equal to about 30° C. to less than or equal to about 100° C.

In one aspect, the heat treating includes tempering the as-cast recycled aluminum alloy component at a temperature of greater than or equal to about 530° C. to less than or equal to about 550° C. for greater than or equal to about 1 hour to less than or equal to about 10 hours, followed by quenching after the heat treating with water at a temperature in the range of greater than or equal to about 30° C. to less than or equal to about 100° C., and then ageing the recycled aluminum alloy component at a temperature of greater than or equal to about 130° C. to less than or equal to about 190° C. for greater than or equal to about 1 hour to less than or equal to about 10 hours.

In certain aspects, the as-cast recycled aluminum alloy component has a yield strength of greater than or equal to about 210 MPa.

Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

FIG. 1 shows a conventional growth mechanism of an iron (Fe)-rich phase in an aluminum-silicon alloy that involves faceted growth along a well-defined and consistent direction that forms platelet-shaped iron-containing intermetallics.

FIG. 2 shows a non-faceted growth mechanism of an iron (Fe)-rich phase in an aluminum-silicon alloy modified in accordance with certain aspects of the present disclosure to have trace alloying elements to generate a non-faceted intermetallic fibrous morphology that enhances iron content, while providing adequate yield strength and ductility.

FIG. 3 shows a micrograph of an aluminum-silicon alloy having an iron (Fe)-rich phase formed via faceted growth with platelet-shaped iron-containing intermetallics. The scale bar is 20 micrometers.

FIG. 4 shows a micrograph of an aluminum-silicon alloy having an iron (Fe)-rich phase formed via non-faceted growth with non-faceted intermetallic fibrous iron-containing intermetallics, in accordance with certain aspects of the present disclosure. The scale bar is 20 micrometers.

Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific compositions, components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, elements, compositions, steps, integers, operations, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Although the open-ended term “comprising,” is to be understood as a non-restrictive term used to describe and claim various embodiments set forth herein, in certain aspects, the term may alternatively be understood to instead be a more limiting and restrictive term, such as “consisting of” or “consisting essentially of.” Thus, for any given embodiment reciting compositions, materials, components, elements, features, integers, operations, and/or process steps, the present disclosure also specifically includes embodiments consisting of, or consisting essentially of, such recited compositions, materials, components, elements, features, integers, operations, and/or process steps. In the case of “consisting of,” the alternative embodiment excludes any additional compositions, materials, components, elements, features, integers, operations, and/or process steps, while in the case of “consisting essentially of,” any additional compositions, materials, components, elements, features, integers, operations, and/or process steps that materially affect the basic and novel characteristics are excluded from such an embodiment, but any compositions, materials, components, elements, features, integers, operations, and/or process steps that do not materially affect the basic and novel characteristics can be included in the embodiment.

Any method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed, unless otherwise indicated.

When a component, element, or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other component, element, or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

Although the terms first, second, third, etc. may be used herein to describe various steps, elements, components, regions, layers and/or sections, these steps, elements, components, regions, layers and/or sections should not be limited by these terms, unless otherwise indicated. These terms may be only used to distinguish one step, element, component, region, layer or section from another step, element, component, region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first step, element, component, region, layer or section discussed below could be termed a second step, element, component, region, layer or section without departing from the teachings of the example embodiments.

Spatially or temporally relative terms, such as “before,” “after,” “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially or temporally relative terms may be intended to encompass different orientations of the device or system in use or operation in addition to the orientation depicted in the figures.

Throughout this disclosure, the numerical values represent approximate measures or limits to ranges to encompass minor deviations from the given values and embodiments having about the value mentioned as well as those having exactly the value mentioned. Other than in the working examples provided at the end of the detailed description, all numerical values of parameters (e.g., of quantities or conditions) in this specification, including the appended claims, are to be understood in certain embodiments as being modified by the term “about” whether or not “about” actually appears before the numerical value, while in other embodiments, are precisely or exactly the value or parameter specified. “About” indicates that the stated numerical value allows some slight imprecision (with some approach to exactness in the value; approximately or reasonably close to the value; nearly). If the imprecision provided by “about” is not otherwise understood in the art with this ordinary meaning, then “about” as used herein indicates at least variations that may arise from ordinary methods of measuring and using such parameters. For example, “about” may comprise a variation of less than or equal to 5%, optionally less than or equal to 4%, optionally less than or equal to 3%, optionally less than or equal to 2%, optionally less than or equal to 1%, optionally less than or equal to 0.5%, and in certain aspects, optionally less than or equal to 0.1%. By way of example, if a range is specified to be greater than or equal to about A to less than or equal to about B, this encompasses not only the stated range, but also a range that includes greater than or equal to exactly A to less than or equal to exactly B, as well greater than exactly A to less than exactly B in other embodiments.

In addition, disclosure of ranges includes disclosure of all values and further divided ranges within the entire range, including endpoints and sub-ranges given for the ranges.

As used herein, unless otherwise indicated, amounts expressed in weight and mass are used interchangeably, but should be understood to reflect a mass of a given component.

As used herein, the terms “composition” and “material” are used interchangeably to refer broadly to a substance containing at least the preferred chemical constituents, elements, or compounds, but which may also comprise additional elements, compounds, or substances, including trace amounts of impurities, unless otherwise indicated. An “X-based” composition or material broadly refers to compositions or materials in which “X” is the single largest constituent on a mass percentage (%) basis. This may include compositions or materials having, by mass/weight, greater than 50% X, as well as those having, by weight, less than 50% X, so long as X is the single largest constituent of the composition or material based upon its overall weight.

Example embodiments will now be described more fully with reference to the accompanying drawings. Aluminum alloys include aluminum (Al), as well as other alloying elements, such as silicon (Si), magnesium (Mg), and iron (Fe), among others. As used herein, the term “aluminum alloy” refers to a material that comprises, by mass, greater than or equal to about 87% by mass aluminum (Al) and one or more other elements (referred to as “alloying” elements) selected to impart certain desirable properties to the material that are not exhibited by pure aluminum. Aluminum alloys described herein may be represented by a sequence of chemical symbols for the base element (e.g., Al) and its major alloying elements (e.g., Si, Mg, and Fe), with nominative designations having the alloying elements arranged in order of decreasing mass percent (or alphabetically if percentages are similar or equal) after the primary Al matrix, e.g., an Al—Si—Mg—Fe alloy. Where a number precedes the chemical symbol for one or more of the alloying elements, it represents the average mass percent of that element in the alloy composition. For example, an aluminum alloy comprising, by mass, 7% silicon (Si), 0.25% iron (Fe), and the balance Al may be represented or referred to as an Al-75i-0.25Fe alloy.

Aluminum-based alloys may be used to form lightweight solid components or structural components (e.g., load-bearing), for example, for vehicles. Aluminum-based alloys are particularly suitable for use to form components of an automobile or other vehicles (e.g., motorcycles, boats, tractors, buses, motorcycles, mobile homes, campers, and tanks), but they may also be used in a variety of other industries and applications, including aerospace components, consumer goods, devices, buildings (e.g., houses, offices, sheds, warehouses), office equipment and furniture, and industrial equipment machinery, agricultural or farm equipment, or heavy machinery, by way of non-limiting example. Cast aluminum components may include vehicle body components, chassis components, and/or propulsion system components. Non-limiting examples of automotive components include hoods, pillars (e.g., A-pillars, hinge pillars, B-pillars, C-pillars, and the like), panels, including structural panels, door panels, and door components, interior floors, floor pans, roofs, exterior surfaces, underbody shields, wheels, rims, control arms and other suspension components.

As described above, aluminum-based alloy structural castings formed of high pure (e.g., 100% primary pure/virgin aluminum) can be have several downsides, such as having a substantial carbon dioxide (CO₂) footprint in production of primary/virgin aluminum from aluminum oxide (Al₂O₃) via the electrolysis process (for example, generating from 8 to 22 kg of CO₂per kg Al depending on type of electricity used), sustainability concerns in mining aluminum oxide (Al₂O₃), and relatively high expense. Aluminum is a highly recyclable product and thus it would be advantageous to increase an amount of recycled post-consumer aluminum scrap in aluminum-based alloy structural cast components. However, post-consumer aluminum scrap is a blend of various difference types of recycled aluminum sources and has a relatively high iron content for use in load-bearing structural components. Iron (Fe) is insoluble in aluminum in the solid state and may form a variety of iron-rich intermetallic phases. For example, iron (Fe) as an impurity will combine with aluminum (Al) and silicon (Si) atoms to form iron-rich intermetallics, which tend to act as crack initiators in deformation, degrading fracture toughness, ductility and fatigue durability of aluminum-silicon alloy castings. As a result, iron may have an adverse impact on the final mechanical properties of an aluminum alloy. The iron-rich intermetallic compounds have a plate morphology that may form crack planes, and thus lower toughness, ductility, and fatigue resistance. Additionally, the iron-rich intermetallic compounds may act as a crack initiator and provide a lower resistance crack path. Thus, as noted above, iron content is restricted to low levels for structural castings of aluminum-based alloys, for example, to less than or equal to 0.15 mass %. When iron content is restricted in this manner, only a very limited fraction of recycled aluminum scraps can be used.

If the iron (Fe)-rich phase/intermetallics can be tailored to become less harmful, a higher level of impurity iron (Fe) can be tolerated in the aluminum-based alloy forming cast structural components. Adding chromium (Cr) and manganese (Mn) can transform an iron (Fe)-rich phase from an undesirable Al—Fe—Si phase to Al-(M, Fe)—Si phase, where M is Cr or Mn, which is less harmful to ductility and fatigue durability, but unfortunately a total volume of iron (Fe)-rich intermetallic phase will increase in the mechanism, which can be undesirable to mechanical performance in certain applications. Thus, for certain applications, when relying on the Cr/Mn neutralizing effect, a maximum iron (Fe) content that can be tolerated without sacrificing mechanical property is typically less than about 0.25%. To further increase an upper limit of impurity iron (Fe), for example, to far greater levels, such as 0.4% or even higher, a new mechanism is needed to enhance iron content in the aluminum-based alloy without detracting from desired mechanical performance.

In various aspects, the present disclosure provides a cast solid component that may have a tailored aluminum (Al)-based alloy chemistry. The aluminum alloy may have a higher tolerance for iron impurity than is conventionally acceptable, and thus permits inclusion of high levels of recycled aluminum scrap in production. As discussed herein, the present disclosure achieves this objective and provides aluminum-based alloys having relatively high iron content, for example, greater than or equal to about 0.2 mass % or higher, so that increased iron (Fe) tolerance permits much higher levels of post-consumer aluminum (Al) scraps from end-of-life products to be used, which can reduce carbon dioxide emissions by up to about 90% and reduce attendant costs of the material. Thus, the present disclosure provides a tailored aluminum (Al)-based alloy chemistry having a high tolerance limit for iron impurity (in some cases, in excess of 0.4% by mass), which can be produced using a high fraction of recycled aluminum (Al) scrap. Furthermore, the tailored aluminum alloy forms a heat-treated cast aluminum alloy component that exhibits good mechanical performance, including high yield strength and high ductility/elongation to fracture.

In various aspects, the present disclosure contemplates tailoring the aluminum alloy composition in a manner that facilities a change to a growth mechanism of iron (Fe)-rich phases or intermetallics distributed in a matrix of the aluminum alloy, while preserving the iron (Fe)-rich phase crystallography. By way of background, FIG. 1 shows a conventional growth mechanism 50 of an iron (Fe)-rich phase that involves faceted growth along a well-defined and consistent direction. In FIG. 1 , a molten alloy has a solid region 62 forming that may be an iron (Fe)-rich intermetallic phase. As shown in the inset, there are solid-phase atoms 70 (e.g., particles or crystals), as well as liquid-phase atoms 72 as they are in the process of solidifying at a solid-liquid interface 74 to form the growing solid region 62. When crystallization of an iron-rich intermetallic phase initiates, aluminum and iron atoms (e.g., solid-phase atoms 70) will form along-range ordered lattice as a solid phase (e.g., solid region 62). Then aluminum and iron atoms in liquid (e.g., liquid-phase atoms 72) will attach to solid-liquid interface 74 along a preferred direction which is referred to as growth direction.

Arrows 76 show a growth direction for the liquid-phase atoms 72 as they are deposited onto the solid-phase atoms 70 in a single direction and considered to be a faceted growth mechanism. In this manner, growth occurs along a well-defined and consistent direction 76. Thus, a faceted/solid liquid interface forms a smooth surface. In this manner, the faceted growth mechanism 50 produces a faceted crystal structure 80 having rectangular and sharp edges 82 and thus an undesirable plate-like morphology.

The micrograph in FIG. 3 shows a two-dimensional conventional coarse-unmodified iron (Fe)-rich phase with a plate-shaped morphology. For example, the iron (Fe)-rich intermetallic phases thus appear as “plate” morphologies in three dimensions, but can appear as needle-like structures in two-dimensional metallographic sections like that shown in FIG. 3 with a plurality of plate or platelet-like structures shown as arrows 90 in the microstructure.

A platelet-like shape is typically flattened, for example, a plate or flake that may have a polygonal (e.g., rectangular or trapezoidal) or angular shape. In a two-dimensional (2D) section, a plate-shaped structure 90 can play an important role in affecting mechanical properties, as discussed above. For example, a plate-like morphology can increase stress concentrations at tips or sharp edges 82 of the iron (Fe)-rich phase structure. In this aspect, the aspect ratio (AR) when considering the two dimensional sectional characterization may be as defined as AR=L/H of the structure, where L is the maximum Feret length (here the major lateral axis) and H is the minimum Feret length. A platelet or plate-like shape generally defines a particle with an AR of greater than or equal to about 2 to less than or equal to about 100 and without modification, may be greater than or equal to 3 to less than or equal to about 10 in certain variations.

In certain aspects, the present disclosure contemplates a microstructure in a heat-treated cast aluminum alloy component that is substantially free of faceted iron-containing intermetallics having a platelet or plate-like shape. The term “substantially free” as referred to herein means that the plate-like faceted iron (Fe)-rich phase microstructures are absent to the extent that that physical properties and limitations attendant with their presence are avoided. In certain embodiments, a solidified aluminum alloy part or component that is “substantially free” faceted iron-containing intermetallics comprises less than about 10% by volume of the faceted iron-containing intermetallics, optionally less than about 5% by volume, optionally less than about 4% by volume, optionally less than about 3% by volume, optionally less than about 2% by volume, optionally less than about 1% by volume, optionally less than about 0.5% by volume and in certain embodiments comprises 0% by volume of the faceted iron-containing intermetallics.

In various aspects, the present disclosure contemplates tailoring the aluminum alloy composition in a manner that facilities a change to a growth mechanism of non-faceted iron (Fe)-rich phases or intermetallics that do not have a platelet or plate-like shape, while preserving the same iron (Fe)-rich phase crystallography as a faceted iron (Fe)-rich phase. FIG. 2 shows a non-faceted growth mechanism 100 of an iron (Fe)-rich phase in accordance with certain aspects of the present disclosure. In FIG. 2 , a solid region 110 is forming in a molten alloy 112. As shown in the inset, there are solid-phase atoms 120 (e.g., particles or crystals), as well as liquid-phase atoms 122 as they are in the process of solidifying at a solid-liquid interface 130 to form the growing solid region 110.

Then aluminum and iron atoms in liquid (e.g., liquid-phase atoms 122) will attach to the solid-liquid interface 130 along different directions and may further branch in a non-faceted growth mechanism. Arrows 124 show growth direction(s) at the solid-liquid interface 130 for the liquid-phase atoms 122 as they are deposited onto the solid-phase atoms 120. In FIG. 2 , this is a non-faceted growth direction(s) with branching that forms a desirable fibrous and more rounded morphology. The growth direction(s) 124 can occur in several directions to promote the branching. In this manner, the non-faceted growth mechanism 100 produces a non-faceted crystal structure 140 having multiple rounded branches or filaments 142 that defines a desirable morphology that is free of plate-like or platelet-shaped intermetallic compounds.

As shown in the two-dimensional micrograph in FIG. 4 , a desirable morphology includes a refined, modified iron (Fe)-rich intermetallic phase, which includes a plurality of rounded fibers 150, which may be described as a non-faceted rounded morphology. The fibers 150 in the iron (Fe)-rich phase may have an aspect ratio when considering the two dimensional sectional characterization, AR=L/H, where L is the maximum Feret length (here the major lateral axis) and H is the minimum Feret length. In certain aspects, a fiber may have an AR of greater than or equal to about 1 to less than or equal to about 3. In certain aspects, a heat treated aluminum alloy component thus comprises an iron-containing intermetallic including iron (Fe), silicon (Si), and aluminum (Al) and the iron-containing intermetallic is spheroidized. The iron-containing intermetallic may have an average equivalent diameter of greater than or equal to about 1 micrometer to less than or equal to about 5 micrometers.

The present disclosure thus contemplates changing the growth mechanism of an iron (Fe)-rich phase by tailoring the chemistry of the aluminum alloy, without changing the crystallographic structure. To modify the morphology of iron (Fe)-rich phase to become fine and fibrous, as shown in FIG. 2 , and to tolerate much higher levels of iron impurity without increasing an overall volume of the iron (Fe)-rich intermetallics in the aluminum alloy matrix, certain select trace elements can be added as alloying elements at low levels to desirably change the growth mechanism and avoid formation of plate-like intermetallic morphology. Without being bound by any particular theory, it is theorized that these trace alloying element(s) may be absorbed/segregated onto specific planes and change stacking sequence at the liquid-solid interface, impeding attachment of aluminum/iron onto the preferred growth plane. The presence of the trace alloying elements is believed to impede growth in the original preferred direction and promote branching. In order to modify the iron (Fe)-rich phase (for example, comprising aluminum, iron, and silicon), a trace alloying element is selected to have an atomic radius that is approximately 1.5 times or more greater than a radius of an iron atom, which is about 156 pm, so that the alloying element has a radius of greater than or equal to about 220 pm. Further, the alloying element may be selected to be non-toxic and not radioactive.

In accordance with various aspects of the present disclosure, the trace alloying element is selected from the group consisting of: barium (Ba), lanthanum (La), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and combinations thereof. In certain variations, the alloying element is selected from the group consisting of: barium (Ba), samarium (Sm), europium (Eu), erbium (Er), and combinations thereof.

The trace alloying element may be added to the aluminum alloy at greater than or equal to about 50 parts per million (ppm) to less than or equal to about 500 ppm and optionally at greater than or equal to about 50 ppm to less than or equal to about 300 ppm by mass of the aluminum alloy. For example, the trace alloying element may be present at about 50 ppm, optionally at about 100 ppm, optionally at about 150 ppm, optionally at about 200 ppm, optionally at about 250 ppm, optionally at about 300 ppm, optionally at about 350 ppm, optionally at about 400 ppm, optionally at about 450 ppm, and optionally at about 500 ppm. It should be noted that the trace alloying elements are not typically found as alloying ingredients in aluminum-silicon alloys and thus not generally present as impurities or contaminants, but rather are intentionally added elements for the purpose of modifying growth mechanism of iron (Fe)-rich phases within the aluminum-silicon alloy matrix. In this manner, by adding the trace alloying element to the aluminum alloy, it enables a higher tolerance for iron to be added and thus permits higher levels of scrap aluminum to be included and recycled in the aluminum alloy, thus reducing a carbon footprint per component made and fostering sustainability at the same time.

In various aspects, the present disclosure contemplates a heat-treated cast recycled aluminum alloy component for a vehicle formed from an aluminum alloy. The aluminum alloy comprises silicon (Si) at greater than or equal to about 5% to less than or equal to about 11% by mass of the aluminum alloy and optionally comprises silicon (Si) at greater than or equal to about 6.5% to less than or equal to about 8% by mass of the aluminum alloy.

The modification to the growth mechanism described above to facilitate non-faceted growth works for a eutectic reaction in the aluminum alloy, so the content of the aluminum alloy is generally limited to less than or equal to about 1.1% by mass to remain as a eutectic reaction and avoid a primary iron (Fe)-rich phase. Thus, the aluminum alloy may have iron (Fe) at greater than or equal to about 0.2% to less than or equal to about 1.1% by mass of the aluminum alloy, optionally greater than or equal to about 0.25% by mass to less than or equal to about 1.1% by mass, optionally greater than or equal to about 0.25% by mass to less than or equal to about 1.1% by mass, and optionally greater than or equal to about 0.4% by mass to less than or equal to about 1.1% by mass of the aluminum alloy. In certain variations, iron (Fe) may be present at greater than or equal to about 0.2% to less than or equal to about 0.8% by mass of the aluminum alloy, optionally at greater than or equal to about 0.2% to less than or equal to about 0.6% by mass of the aluminum alloy, at greater than or equal to about 0.4% to less than or equal to about 0.8% by mass of the aluminum alloy, or optionally at greater than or equal to about 0.4% to less than or equal to about 0.6% by mass of the aluminum alloy.

In this manner, the aluminum alloy may comprise greater than or equal to about 70% by mass of post-consumer aluminum recycling scrap, optionally greater than or equal to about 75% by mass of aluminum recycling scrap, optionally greater than or equal to about 80% by mass of aluminum recycling scrap, optionally greater than or equal to about 85% by mass of aluminum recycling scrap, and optionally greater than or equal to about 90% by mass of aluminum recycling scrap. Thus, the aluminum alloy may have less than or equal to 30% by mass pure or virgin aluminum, optionally less than or equal to about 25% by mass pure or virgin aluminum, optionally less than or equal to about 20% by mass pure or virgin aluminum, optionally less than or equal to about 15% by mass pure or virgin aluminum, and in certain variations, optionally less than or equal to about 10% by mass pure or virgin aluminum.

The aluminum alloy may have magnesium (Mg) at less than or equal to about 0.5% by mass of the aluminum alloy, for example, at greater than 0 to less than or equal to about 0.5% by mass of the aluminum alloy, optionally greater than or equal to about 0.3% to less than or equal to about 0.4% by mass of the aluminum alloy.

The aluminum alloy may have copper (Cu) at less than or equal to about 0.5% by mass of the aluminum alloy, for example, at greater than 0 to less than or equal to about 0.5% by mass of the aluminum alloy, optionally greater than or equal to about 0% to less than or equal to about 0.1% by mass of the aluminum alloy.

The aluminum alloy may contain zinc (Zn) at less than or equal to about by mass of the aluminum alloy, for example, at greater than 0 to less than or equal to about 0.5% by mass of the aluminum alloy, optionally greater than or equal to about 0% to less than or equal to about 0.1% by mass of the aluminum alloy.

The aluminum alloy may have titanium (Ti) at less than or equal to about by mass of the aluminum alloy, for example, at greater than 0 to less than or equal to about 0.2% by mass of the aluminum alloy, optionally greater than or equal to about 0% to less than or equal to about 0.1% by mass of the aluminum alloy.

The aluminum alloy may have chromium (Cr) at less than or equal to about 0.02% by mass of the aluminum alloy, for example, at greater than 0 to less than or equal to about 0.02% by mass of the aluminum alloy.

The aluminum alloy may have manganese (Mn) at less than or equal to about 0.05% by mass of the aluminum alloy, for example, at greater than 0 to less than or equal to about 0.05% by mass of the aluminum alloy.

The aluminum alloy may have strontium (Sr) at less than or equal to about 200 parts per million (ppm) by mass of the aluminum alloy, for example, at greater than 0 to less than or equal to about 200 ppm of the aluminum alloy.

A cumulative amount of impurities and contaminants may be present at less than or equal to about 0.3% by mass, optionally less than or equal to about 0.1% by mass, optionally less than or equal to about 0.05% by mass, and in certain variations, optionally less than or equal to about 0.01% by mass of the aluminum-based alloy. Notably, impurities or contaminants are not intentionally introduced into the aluminum alloy like the alloying ingredients, including the trace alloying elements, discussed above.

A balance of the aluminum-based alloy may comprise aluminum (Al), for example, greater than or equal to about 87% by mass, optionally greater than or equal to about 88% by mass, optionally greater than or equal to about 89% by mass, or optionally greater than or equal to about 90% by mass aluminum (Al).

In certain variations, an aluminum alloy for use in forming recycled heat-treated cast aluminum alloy components may comprise silicon (Si) at greater than or equal to about 5% to less than or equal to about 11% by mass, magnesium (Mg) at less than or equal to about 0.5% by mass, iron (Fe) at greater than or equal to about 0.2% to less than or equal to about 1.1% by mass, copper (Cu) at less than or equal to about 0.5% by mass, zinc (Zn) at less than or equal to about 0.5% by mass, titanium (Ti) at less than or equal to about 0.2% by mass, chromium (Cr) at less than or equal to about 0.02% by mass, manganese (Mn) at less than or equal to about 0.05% by mass, strontium (Sr) at less than or equal to about 200 ppm, an alloying element at greater than or equal to about 50 ppm to less than or equal to about 500 ppm, wherein the alloying element is selected from the group consisting of: barium (Ba), lanthanum (La), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and combinations thereof, and a balance aluminum (Al) and optional impurities.

In certain other variations, an aluminum alloy for use in forming recycled heat-treated cast aluminum alloy components may consist essentially of silicon (Si) at greater than or equal to about 5% to less than or equal to about 11% by mass, magnesium (Mg) at greater than or equal to 0 to less than or equal to about 0.5% by mass, iron (Fe) at greater than or equal to about 0.2% to less than or equal to about 1.1% by mass, copper (Cu) at greater than or equal to 0 to less than or equal to about by mass, zinc (Zn) at greater than or equal to 0 to less than or equal to about 0.5% by mass, titanium (Ti) at greater than or equal to 0 to less than or equal to about 0.2% by mass, chromium (Cr) at greater than or equal to 0 to less than or equal to about by mass, manganese (Mn) at greater than or equal to 0 to less than or equal to about 0.05% by mass, strontium (Sr) at greater than or equal to 0 to less than or equal to about 200 ppm, an alloying element at greater than or equal to about 50 ppm to less than or equal to about 500 ppm, wherein the alloying element is selected from the group consisting of: barium (Ba), lanthanum (La), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and combinations thereof, optional impurities present at less than or equal to about 0.3% by mass, and a balance aluminum (Al).

In certain other variations, an aluminum alloy for use in forming recycled heat-treated cast aluminum alloy components consists of silicon (Si) at greater than or equal to about 5% to less than or equal to about 11% by mass, magnesium (Mg) at greater than or equal to 0 to less than or equal to about 0.5% by mass, iron (Fe) at greater than or equal to about 0.2% to less than or equal to about 1.1% by mass, copper (Cu) at greater than or equal to 0 to less than or equal to about 0.5% by mass, zinc (Zn) at greater than or equal to 0 to less than or equal to about 0.5% by mass, titanium (Ti) at greater than or equal to 0 to less than or equal to about 0.2% by mass, chromium (Cr) at greater than or equal to 0 to less than or equal to about 0.02% by mass, manganese (Mn) at greater than or equal to 0 to less than or equal to about 0.05% by mass, strontium (Sr) at greater than or equal to 0 to less than or equal to about 200 ppm, an alloying element at greater than or equal to about 50 ppm to less than or equal to about 500 ppm, wherein the alloying element is selected from the group consisting of: barium (Ba), lanthanum (La), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and combinations thereof, optional impurities present at less than or equal to about 0.3% by mass, and a balance aluminum (Al).

In certain variations, an aluminum alloy for use in forming recycled heat-treated cast aluminum alloy components may comprise silicon (Si) at greater than or equal to about 6.5% to less than or equal to about 8% by mass, magnesium (Mg) at greater than 0.3 to less than or equal to about 0.4% by mass, iron (Fe) at greater than or equal to about 0.2% to less than or equal to about 0.6% by mass, copper (Cu) at less than or equal to about 0.1% by mass, zinc (Zn) at less than or equal to about 0.1% by mass, titanium (Ti) at less than or equal to about 0.2% by mass, chromium (Cr) at less than or equal to about 0.02% by mass, manganese (Mn) at less than or equal to about by mass, strontium (Sr) at less than or equal to about 200 ppm, an alloying element at greater than or equal to about 50 ppm to less than or equal to about 300 ppm, wherein the alloying element is selected from the group consisting of: barium (Ba), lanthanum (La), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and combinations thereof, a balance aluminum (Al) and optional impurities.

In certain variations, an aluminum alloy for use in forming recycled heat-treated cast aluminum alloy components may consist essentially of silicon (Si) at greater than or equal to about 6.5% to less than or equal to about 8% by mass, magnesium (Mg) at greater than 0.3 to less than or equal to about 0.4% by mass, iron (Fe) at greater than or equal to about 0.2% to less than or equal to about 0.6% by mass, copper (Cu) at greater than or equal to 0 to less than or equal to about 0.1% by mass, zinc (Zn) at greater than or equal to 0 to less than or equal to about 0.1% by mass, titanium (Ti) at greater than or equal to 0 to less than or equal to about 0.2% by mass, chromium (Cr) at greater than or equal to 0 to less than or equal to about 0.02% by mass, manganese (Mn) at greater than or equal to 0 to less than or equal to about 0.05% by mass, strontium (Sr) at greater than or equal to 0 to less than or equal to about 200 ppm, an alloying element at greater than or equal to about 50 ppm to less than or equal to about 300 ppm, wherein the alloying element is selected from the group consisting of: barium (Ba), lanthanum (La), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and combinations thereof, optional impurities present at less than or equal to about 0.3% by mass, and a balance aluminum (Al).

In certain variations, an aluminum alloy for use in forming recycled heat-treated cast aluminum alloy components may consist of silicon (Si) at greater than or equal to about 6.5% to less than or equal to about 8% by mass, magnesium (Mg) at greater than 0.3 to less than or equal to about 0.4% by mass, iron (Fe) at greater than or equal to about 0.2% to less than or equal to about 0.6% by mass, copper (Cu) at greater than or equal to 0 to less than or equal to about 0.1% by mass, zinc (Zn) at greater than or equal to 0 to less than or equal to about 0.1% by mass, titanium (Ti) at greater than or equal to 0 to less than or equal to about 0.2% by mass, chromium (Cr) at greater than or equal to 0 to less than or equal to about 0.02% by mass, manganese (Mn) at greater than or equal to 0 to less than or equal to about 0.05% by mass, strontium (Sr) at greater than or equal to 0 to less than or equal to about 200 ppm, an alloying element at greater than or equal to about 50 ppm to less than or equal to about 300 ppm, wherein the alloying element is selected from the group consisting of: barium (Ba), lanthanum (La), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and combinations thereof, optional impurities present at less than or equal to about 0.3% by mass, and a balance aluminum (Al).

In yet other variations, an aluminum alloy for use in forming recycled heat-treated cast aluminum alloy components may comprise silicon (Si) at greater than or equal to about 6.5% to less than or equal to about 8% by mass, magnesium (Mg) at greater than 0.3 to less than or equal to about 0.4% by mass, iron (Fe) at greater than or equal to about 0.4% to less than or equal to about 0.8% by mass, copper (Cu) at less than or equal to about 0.1% by mass, zinc (Zn) at less than or equal to about 0.1% by mass, titanium (Ti) at less than or equal to about 0.2% by mass, chromium (Cr) at less than or equal to about 0.02% by mass, manganese (Mn) at less than or equal to about 0.05% by mass, strontium (Sr) at less than or equal to about 200 ppm, an alloying element at greater than or equal to about 50 ppm to less than or equal to about 300 ppm, wherein the alloying element is selected from the group consisting of: barium (Ba), lanthanum (La), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and combinations thereof, a balance aluminum (Al) and optional impurities.

In certain other variations, an aluminum alloy for use in forming recycled heat-treated cast aluminum alloy components may consist essentially of silicon (Si) at greater than or equal to about 6.5% to less than or equal to about 8% by mass, magnesium (Mg) at greater than 0.3 to less than or equal to about 0.4% by mass, iron (Fe) at greater than or equal to about 0.4% to less than or equal to about 0.8% by mass, copper (Cu) at greater than or equal to 0 to less than or equal to about 0.1% by mass, zinc (Zn) at greater than or equal to 0 to less than or equal to about 0.1% by mass, titanium (Ti) at greater than or equal to 0 to less than or equal to about 0.2% by mass, chromium (Cr) at greater than or equal to 0 to less than or equal to about 0.02% by mass, manganese (Mn) at greater than or equal to 0 to less than or equal to about 0.05% by mass, strontium (Sr) at greater than or equal to 0 to less than or equal to about 200 ppm, an alloying element at greater than or equal to about 50 ppm to less than or equal to about 300 ppm, wherein the alloying element is selected from the group consisting of: barium (Ba), lanthanum (La), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and combinations thereof, optional impurities present at less than or equal to about 0.3% by mass, and a balance aluminum (Al).

In certain further variations, an aluminum alloy for use in forming recycled heat-treated cast aluminum alloy components may consist of silicon (Si) at greater than or equal to about 6.5% to less than or equal to about 8% by mass, magnesium (Mg) at greater than 0.3 to less than or equal to about 0.4% by mass, iron (Fe) at greater than or equal to about 0.4% to less than or equal to about 0.8% by mass, copper (Cu) at greater than or equal to 0 to less than or equal to about 0.1% by mass, zinc (Zn) at greater than or equal to 0 to less than or equal to about 0.1% by mass, titanium (Ti) at greater than or equal to 0 to less than or equal to about 0.2% by mass, chromium (Cr) at greater than or equal to 0 to less than or equal to about 0.02% by mass, manganese (Mn) at greater than or equal to 0 to less than or equal to about 0.05% by mass, strontium (Sr) at greater than or equal to 0 to less than or equal to about 200 ppm, an alloying element at greater than or equal to about 50 ppm to less than or equal to about 300 ppm, wherein the alloying element is selected from the group consisting of: barium (Ba), lanthanum (La), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and combinations thereof, optional impurities present at less than or equal to about 0.3% by mass, and a balance aluminum (Al).

The present disclosure also contemplates a method of making a recycled aluminum alloy component, such as a component for a vehicle or automobile. Recycled scrap aluminum can be combined with pure/virgin aluminum and then used as a raw material to prepare an ingot with designated chemistry. The ingot can then be processed in a caster to make the desired products or components. Here, greater than or equal to about 70% by mass of the alloy precursor or ingot comprises recycled aluminum scrap as raw material. In certain aspects, the method includes melting an aluminum alloy precursor. The method may comprise melting an aluminum alloy precursor comprising greater than or equal to about 70% by mass aluminum recycling scrap to form a molten alloy. The aluminum alloy precursor may be melted in a casting furnace. The aluminum alloy precursor may have a composition comprising silicon (Si) at greater than or equal to about 5% to less than or equal to about 11% by mass, magnesium (Mg) at less than or equal to about 0.5% by mass, iron (Fe) at greater than or equal to about 0.2% to less than or equal to about 1.1% by mass, copper (Cu) at less than or equal to about 0.5% by mass, zinc (Zn) at less than or equal to about 0.5% by mass, titanium (Ti) at less than or equal to about 0.2% by mass, chromium (Cr) at less than or equal to about 0.02% by mass, manganese (Mn) at less than or equal to about 0.05% by mass, strontium (Sr) at less than or equal to about 200 ppm, and a balance aluminum (Al) and optional impurities. Notably, the aluminum alloy precursor omits the trace alloying element, but generally may otherwise have any of the aluminum alloy compositions described above.

In certain aspects, the aluminum alloy precursor comprises silicon (Si) at greater than or equal to about 6.5% to less than or equal to about 8% by mass, magnesium (Mg) at greater than 0.3 to less than or equal to about 0.4% by mass, iron (Fe) at greater than or equal to about 0.2% to less than or equal to about 0.6% by mass, copper (Cu) at less than or equal to about 0.1% by mass, zinc (Zn) at less than or equal to about 0.1% by mass, titanium (Ti) at less than or equal to about 0.2% by mass, chromium (Cr) at less than or equal to about 0.02% by mass, manganese (Mn) at less than or equal to about 0.05% by mass, strontium (Sr) at less than or equal to about 200 ppm, and a balance aluminum (Al) and optional impurities, but free of the alloying element.

In certain other aspects, the aluminum alloy precursor comprises silicon (Si) at greater than or equal to about 6.5% to less than or equal to about 8% by mass, magnesium (Mg) at greater than 0.3 to less than or equal to about 0.4% by mass, iron (Fe) at greater than or equal to about 0.4% to less than or equal to about 0.8% by mass, copper (Cu) at less than or equal to about 0.1% by mass, zinc (Zn) at less than or equal to about 0.1% by mass, titanium (Ti) at less than or equal to about 0.2% by mass, chromium (Cr) at less than or equal to about 0.02% by mass, manganese (Mn) at less than or equal to about 0.05% by mass, strontium (Sr) at less than or equal to about 200 ppm, a balance aluminum (Al) and optional impurities, but free of the alloying element.

The method further comprises introducing a master alloy into the molten alloy. The master alloy comprises a matrix element selected from the group consisting of: aluminum (Al), magnesium (Mg), silicon (Si), and combinations thereof. In certain aspects, a matrix element of the master alloy may include aluminum (Al) and magnesium (Mg). The master alloy also comprises an alloying element selected from the group consisting of: barium (Ba), lanthanum (La), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and combinations thereof. The alloying element is present in the master alloy at greater than or equal to about 2% to less than or equal to about 50% by mass, optionally at greater than or equal to about 5% to less than or equal to about 30% by mass. In certain aspects, the master alloy is added at greater than or equal to about 0.01% to less than or equal to about 2.5% by mass to the molten alloy. The method further comprises casting the molten alloy by solidifying at a maximum rate of cooling of less than or equal to about 20° C./second to form an as-cast recycled aluminum alloy component

In certain aspects, the method further comprises heat treating the as-cast recycled aluminum alloy component to be substantially free of faceted iron-containing intermetallics having a platelet shape and to have at least one region having a yield strength of greater than or equal to about 180 MPa.

In certain aspects, the methods may further comprise: (i) melt refining of the molten alloy and degassing prior to the introducing the master alloy; (ii) melt refining of the molten alloy and degassing after the introducing the master alloy and prior to the casting; or both (i) and (ii). Melt refining and degassing typically include adding refining agent and introducing nitrogen gas or inert gas bubbles into the melt to reduce hydrogen content and inclusion content.

In certain variations, the heat treating comprises solution heat treating the as-cast recycled aluminum alloy component at a temperature of greater than or equal to about 500° C. to less than or equal to about 550° C., optionally greater than or equal to about 530° C. to less than or equal to about 550° C., for greater than or equal to about 1 hour to less than or equal to about 10 hours.

In other variations, the heat treating comprises ageing the as-cast recycled aluminum alloy component at a temperature of greater than or equal to about 130° C. to less than or equal to about 190° C. for greater than or equal to about 1 hour to less than or equal to about 10 hours.

In yet other aspects, the methods further comprise quenching after the heat treating with water at a temperature in the range of greater than or equal to about 30° C. to less than or equal to about 100° C., for example, in one variation, about 60° C.

In one variation, the heat treating comprises solution heat treating the as-cast recycled aluminum alloy component at a temperature of greater than or equal to about 500° C. to less than or equal to about 550° C. for greater than or equal to about 1 hour to less than or equal to about 10 hours, followed by quenching after the heat treating with water at a temperature in the range of greater than or equal to about 30° C. to less than or equal to about 100° C., and then ageing the as-cast recycled aluminum alloy component at a temperature of greater than or equal to about 130° C. to less than or equal to about 190° C. for greater than or equal to about 1 hour to less than or equal to about 10 hours.

The heat-treated cast aluminum alloy components formed of such aluminum alloys in the above-described methods are substantially free of faceted iron-containing intermetallics having a platelet shape and instead may have non-faceted iron-containing intermetallics, which may have a non-faceted rounded morphology, such as a coral-like fiber morphology. For example, the heat-treated cast aluminum alloy component in certain variations comprises an iron-containing intermetallic comprising iron (Fe), silicon (Si), and aluminum (Al) and the iron-containing intermetallic is spheroidized after heat treatment and has an average equivalent diameter of greater than or equal to about 1 micrometer to less than or equal to about 5 micrometers.

The heat-treated cast aluminum alloy when formed of the aluminum alloys described above in accordance with the methods below may have at least one region with a yield strength of greater than or equal to about 180 MPa, optionally greater than or equal to about 210 MPa, and an elongation or ductility of greater than or equal to about 7%, optionally greater than or equal to about 8%.

The heat-treated cast recycled aluminum alloy component may be an automotive component like those described above. In certain variations, the heat-treated cast aluminum alloy component is an automotive component selected from the group consisting of: an internal combustion engine component, a valve, a piston, a turbocharger component, a rim, a wheel, a subframe, a knuckle, a control arm, a ring and combinations thereof.

The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure. 

What is claimed is:
 1. A heat-treated cast aluminum alloy component for a vehicle formed from an aluminum alloy comprising: silicon (Si) at greater than or equal to about 5% to less than or equal to about 11% by mass; magnesium (Mg) at less than or equal to about 0.5% by mass; iron (Fe) at greater than or equal to about 0.2% to less than or equal to about 1.1% by mass; copper (Cu) at less than or equal to about 0.5% by mass; zinc (Zn) at less than or equal to about 0.5% by mass; titanium (Ti) at less than or equal to about 0.2% by mass; chromium (Cr) at less than or equal to about 0.02% by mass; manganese (Mn) at less than or equal to about 0.05% by mass; strontium (Sr) at less than or equal to about 200 ppm; an alloying element at greater than or equal to about 50 ppm to less than or equal to about 500 ppm, wherein the alloying element is selected from the group consisting of: barium (Ba), lanthanum (La), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and combinations thereof; and a balance aluminum (Al), wherein the heat-treated cast aluminum alloy component is substantially free of faceted iron-containing intermetallics having a platelet shape and at least one region has a yield strength of greater than or equal to about 180 MPa and an elongation of greater than or equal to about 7%.
 2. The heat-treated cast aluminum alloy component of claim 1, wherein the aluminum alloy comprises iron (Fe) at greater than or equal to about 0.25% by mass.
 3. The heat-treated cast aluminum alloy component of claim 1, wherein the aluminum alloy comprises iron (Fe) at greater than or equal to about 0.4% by mass.
 4. The heat-treated cast aluminum alloy component of claim 1, wherein the aluminum alloy comprises: silicon (Si) at greater than or equal to about 6.5% to less than or equal to about 8% by mass; magnesium (Mg) at greater than or equal to about 0.3% to less than or equal to about 0.4% by mass; iron (Fe) at greater than or equal to about 0.2% to less than or equal to about by mass; copper (Cu) at less than or equal to about 0.1% by mass; zinc (Zn) at less than or equal to about 0.1% by mass; and the alloying element at greater than or equal to about 50 ppm to less than or equal to about 300 ppm.
 5. The heat-treated cast aluminum alloy component of claim 1, wherein the aluminum alloy comprises: silicon (Si) at greater than or equal to about 6.5% to less than or equal to about 8% by mass; magnesium (Mg) at greater than or equal to about 0.3% to less than or equal to about 0.4% by mass; iron (Fe) at greater than or equal to about 0.4% to less than or equal to about by mass; copper (Cu) at less than or equal to about 0.1% by mass; zinc (Zn) at less than or equal to about 0.1% by mass; and the alloying element at greater than or equal to about 50 ppm to less than or equal to about 300 ppm.
 6. The heat-treated cast aluminum alloy component of claim 1, wherein the heat-treated cast aluminum alloy component comprises an iron-containing intermetallic that has a non-faceted rounded morphology.
 7. The heat-treated cast aluminum alloy component of claim 1, wherein the heat-treated cast aluminum alloy component comprises an iron-containing intermetallic comprising iron (Fe), silicon (Si), and aluminum (Al) and after heat treatment, the iron-containing intermetallic is spheroidized and has an average equivalent diameter of greater than or equal to about 1 micrometer to less than or equal to about 5 micrometers.
 8. The heat-treated cast aluminum alloy component of claim 1, wherein the alloying element is selected from the group consisting of: barium (Ba), samarium (Sm), europium (Eu), erbium (Er), and combinations thereof.
 9. The heat-treated cast aluminum alloy component of claim 1, wherein the yield strength is greater than or equal to about 210 MPa.
 10. The heat-treated cast aluminum alloy component of claim 1, wherein the heat-treated cast aluminum alloy component is an automotive component.
 11. The heat-treated cast aluminum alloy component of claim 10, wherein the automotive component is selected from the group consisting of: an internal combustion engine component, a valve, a piston, a turbocharger component, a rim, a wheel, a subframe, a knuckle, a control arm, a ring and combinations thereof.
 12. A method of making a recycled aluminum alloy component comprising: melting an aluminum alloy precursor comprising greater than or equal to about 70% by mass aluminum recycling scrap to form a molten alloy, the aluminum alloy precursor having a composition comprising: silicon (Si) at greater than or equal to about 5% to less than or equal to about 11% by mass; magnesium (Mg) at less than or equal to about 0.5% by mass; iron (Fe) at greater than or equal to about 0.2% to less than or equal to about 1.1% by mass; copper (Cu) at less than or equal to about 0.5% by mass; zinc (Zn) at less than or equal to about 0.5% by mass; titanium (Ti) at less than or equal to about 0.2% by mass; chromium (Cr) at less than or equal to about 0.02% by mass; manganese (Mn) at less than or equal to about 0.05% by mass; strontium (Sr) at less than or equal to about 200 ppm; and a balance aluminum (Al); introducing a master alloy into the molten alloy, the master alloy comprising a matrix element selected from the group consisting of: aluminum (Al), magnesium (Mg), silicon (Si), and combinations thereof and an alloying element selected from the group consisting of: barium (Ba), lanthanum (La), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and combinations thereof; and casting by solidifying the molten alloy at a maximum rate of cooling of less than or equal to about 20° C./second to form an as-cast recycled aluminum alloy component; and heat treating the as-cast recycled aluminum alloy component to be substantially free of faceted iron-containing intermetallics having a platelet shape and to have at least one region having a yield strength of greater than or equal to about 180 MPa and an elongation of greater than or equal to about 7%.
 13. The method of claim 12, wherein the alloying element is present in the master alloy at greater than or equal to about 5% to less than or equal to about 30% by mass.
 14. The method of claim 12, wherein the master alloy is added at greater than or equal to about 0.01% to less than or equal to about 2.5% by mass to the molten alloy.
 15. The method of claim 12, further comprising: (i) melt refining of the molten alloy and degassing prior to the introducing the master alloy; (ii) melt refining of the molten alloy and degassing after the introducing the master alloy and prior to the casting; or both (i) and (ii).
 16. The method of claim 12, wherein the heat treating comprises tempering the as-cast recycled aluminum alloy component at a temperature of greater than or equal to about 500° C. to less than or equal to about 550° C. for greater than or equal to about 1 hour to less than or equal to about 10 hours.
 17. The method of claim 12, wherein the heat treating comprises ageing the as-cast recycled aluminum alloy component at a temperature of greater than or equal to about 130° C. to less than or equal to about 190° C. for greater than or equal to about 1 hour to less than or equal to about 10 hours.
 18. The method of claim 12, further comprising quenching after the heat treating with water at a temperature in the range of greater than or equal to about 30° C. to less than or equal to about 100° C.
 19. The method of claim 12, wherein the heat treating comprises tempering the as-cast recycled aluminum alloy component at a temperature of greater than or equal to about 530° C. to less than or equal to about 550° C. for greater than or equal to about 1 hour to less than or equal to about 10 hours, followed by quenching after the heat treating with water at a temperature in the range of greater than or equal to about to less than or equal to about 100° C., and then ageing the recycled aluminum alloy component at a temperature of greater than or equal to about 130° C. to less than or equal to about 190° C. for greater than or equal to about 1 hour to less than or equal to about 10 hours.
 20. The method of claim 12, wherein the yield strength is greater than or equal to about 210 MPa. 